@article {8740, title = {Neem leaf glycoprotein binding to Dectin-1 receptors on dendritic cell induces type-1 immunity through CARD9 mediated intracellular signal to NFκB. [Mass Spectrometry - Proteomics Facility]}, journal = {Cell Commun Signal}, volume = {22}, year = {2024}, month = {2024 Apr 23}, pages = {237}, abstract = {

BACKGROUND: A water-soluble ingredient of mature leaves of the tropical mahogany {\textquoteright}Neem{\textquoteright} (Azadirachta indica), was identified as glycoprotein, thus being named as {\textquoteright}Neem Leaf Glycoprotein{\textquoteright} (NLGP). This non-toxic leaf-component regressed cancerous murine tumors (melanoma, carcinoma, sarcoma) recurrently in different experimental circumstances by boosting prime antitumor immune attributes. Such antitumor immunomodulation, aid cytotoxic T cell (T)-based annihilation of tumor cells. This study focused on identifying and characterizing the signaling gateway that initiate this systemic immunomodulation. In search of this gateway, antigen-presenting cells (APCs) were explored, which activate and induce the cytotoxic thrust in T cells.

METHODS: Six glycoprotein-binding C-type lectins found on APCs, namely, MBR, Dectin-1, Dectin-2, DC-SIGN, DEC205 and DNGR-1 were screened on bone marrow-derived dendritic cells from C57BL/6\ J mice. Fluorescence microscopy, RT-PCR, flow cytometry and ELISA revealed Dectin-1 as the NLGP-binding receptor, followed by verifications through RNAi. Following detection of β-Glucans in NLGP, their interactions with Dectin-1 were explored in silico. Roles of second messengers and transcription factors in the downstream signal were studied by co-immunoprecipitation, western blotting, and chromatin-immunoprecipitation. Intracellularization of FITC-coupled NLGP was observed by processing confocal micrographs of DCs.

RESULTS: Considering extents of hindrance in NLGP-driven transcription rates of the cytokines IL-10 and IL-12p35 by receptor-neutralization, Dectin-1 receptors on dendritic cells were found to bind NLGP through the ligand{\textquoteright}s peripheral β-Glucan chains. The resulting signal phosphorylates PKCδ, forming a trimolecular complex of CARD9, Bcl10 and MALT1, which in turn activates the canonical NFκB-pathway of transcription-regulation. Consequently, the NFκB-heterodimer p65:p50 enhances Il12a transcription and the p50:p50 homodimer represses Il10 transcription, bringing about a cytokine-based systemic-bias towards type-1 immune environment. Further, NLGP gets engulfed within dendritic cells, possibly through endocytic activities of Dectin-1.

CONCLUSION: NLGP{\textquoteright}s binding to Dectin-1 receptors on murine dendritic cells, followed by the intracellular signal, lead to NFκB-mediated contrasting regulation of cytokine-transcriptions, initiating a pro-inflammatory immunopolarization, which amplifies further by the responding immune cells including T cells, alongside their enhanced cytotoxicity. These insights into the initiation of mammalian systemic immunomodulation by NLGP at cellular and molecular levels, may help uncovering its mode of action as a novel immunomodulator against human cancers, following clinical trials.

}, keywords = {Animals, Azadirachta, CARD Signaling Adaptor Proteins, Dendritic Cells, Lectins, C-Type, Mice, Mice, Inbred C57BL, NF-kappa B, Plant Leaves, Protein Binding, Signal Transduction}, issn = {1478-811X}, doi = {10.1186/s12964-024-01576-z}, author = {Ganguly, Nilanjan and Das, Tapasi and Bhuniya, Avishek and Guha, Ipsita and Chakravarti, Mohona and Dhar, Sukanya and Sarkar, Anirban and Bera, Saurav and Dhar, Jesmita and Dasgupta, Shayani and Saha, Akata and Ghosh, Tithi and Das, Juhina and Sk, Ugir Hossain and Banerjee, Saptak and Laskar, Subrata and Bose, Anamika and Baral, Rathindranath} } @article {516, title = {A new C-type lectin (RVsnaclec) purified from venom of Daboia russelii russelii shows anticoagulant activity via inhibition of FXa and concentration-dependent differential response to platelets in a Ca{\texttwosuperior}$^{+}$-independent manner. (Mass spectrometry)}, journal = {Thromb Res}, volume = {134}, year = {2014}, month = {2014 Nov}, pages = {1150-6}, abstract = {

This is the first report on the characterization of a snaclec (RVsnaclec) purified from Daboia russelii russelii venom. The RVsnaclec is a heterodimer of two subunits, α (15.1 kDa) and β (9 kDa). These subunits are covalently linked to form multimeric (αβ)$_{2}$ and (αβ)$_{4}$ structures. Peptide mass fingerprinting analysis of RVsnaclec via LC-MS/MS demonstrated its similarity to snaclecs purified from other viperid snake venoms. Two tryptic peptide sequences of RVsnaclec revealed the putative conserved domains of C-type lectin (CTL). RVsnaclec dose-dependently increased the Ca-clotting time and prothrombin time of platelet-poor plasma (PPP); however, it did not affect the partial thromboplastin time (APTT) or thrombin time of PPP. The in vitro and in vivo anticoagulant activity of RVsnaclec is correlated to its binding and subsequent uncompetitive inhibition of FXa (Ki = 0.52 μmole) in a Ca(2+)-independent manner; however, supplementation with 0.25 mM Ca(2+) enhanced the Xa binding potency of RVsnaclec. Monovalent or polyvalent antivenom failed to neutralize its anticoagulant potency, and RVsnaclec did not inhibit trypsin, chymotrypsin, thrombin or plasmin. RVsnaclec was devoid of hemolytic activity or cytotoxicity against several human cancer cell lines, demonstrated concentration-dependent aggregation and deaggregation of human platelets, and inhibited the ADP-induced aggregation of platelet. RVsnaclec (5.0 mg/kg body weight) was non-lethal to mice and showed no adverse pharmacological effects, suggesting that it has potential as a lead compound for future therapeutic applications in cardiovascular disorders.

}, keywords = {Animals, Anticoagulants, Blood Coagulation, Blood Platelets, Calcium, Factor Xa, Factor Xa Inhibitors, Goats, Humans, Lectins, C-Type, Mice, Platelet Aggregation, Russell{\textquoteright}s Viper, Viper Venoms}, issn = {1879-2472}, doi = {10.1016/j.thromres.2014.09.009}, author = {Mukherjee, Ashis K and Dutta, Sumita and Mackessy, Stephen P} } @article {535, title = {Unique, polyfucosylated glycan-receptor interactions are essential for regeneration of Hydra magnipapillata.}, journal = {ACS Chem Biol}, volume = {9}, year = {2014}, month = {2014 Jan 17}, pages = {147-55}, abstract = {

Cell-cell communications, cell-matrix interactions, and cell migrations play a major role in regeneration. However, little is known about the molecular players involved in these critical events, especially cell surface molecules. Here, we demonstrate the role of specific glycan-receptor interactions in the regenerative process using Hydra magnipapillata as a model system. Global characterization of the N- and O-glycans expressed by H. magnipapillata using ultrasensitive mass spectrometry revealed mainly polyfucosylated LacdiNAc antennary structures. Affinity purification showed that a putative C-type lectin (accession number Q6SIX6) is a likely endogenous receptor for the novel polyfucosylated glycans. Disruption of glycan-receptor interactions led to complete shutdown of the regeneration machinery in live Hydra. A time-dependent, lack-of-regeneration phenotype observed upon incubation with exogenous fuco-lectins suggests the involvement of a polyfucose receptor-mediated signaling mechanism during regeneration. Thus, for the first time, the results presented here provide direct evidence for the role of polyfucosylated glycan-receptor interactions in the regeneration of H. magnipapillata.

}, keywords = {Animals, Carbohydrate Sequence, Hydra, Lectins, C-Type, Molecular Sequence Data, Polysaccharides, Regeneration}, issn = {1554-8937}, doi = {10.1021/cb400486t}, author = {Sahadevan, Sonu and Antonopoulos, Aristotelis and Haslam, Stuart M and Dell, Anne and Ramaswamy, Subramanian and Babu, Ponnusamy} } @article {717, title = {Developmental heterogeneity in DNA packaging patterns influences T-cell activation and transmigration.}, journal = {PLoS One}, volume = {7}, year = {2012}, month = {2012}, pages = {e43718}, abstract = {

Cellular differentiation programs are accompanied by large-scale changes in nuclear organization and gene expression. In this context, accompanying transitions in chromatin assembly that facilitates changes in gene expression and cell behavior in a developmental system are poorly understood. Here, we address this gap and map structural changes in chromatin organization during murine T-cell development, to describe an unusual heterogeneity in chromatin organization and associated functional correlates in T-cell lineage. Confocal imaging of DNA assembly in cells isolated from bone marrow, thymus and spleen reveal the emergence of heterogeneous patterns in DNA organization in mature T-cells following their exit from the thymus. The central DNA pattern dominated in immature precursor cells in the thymus whereas both central and peripheral DNA patterns were observed in na{\"\i}ve and memory cells in circulation. Na{\"\i}ve T-cells with central DNA patterns exhibited higher mechanical pliability in response to compressive loads in vitro and transmigration assays in vivo, and demonstrated accelerated expression of activation-induced marker CD69. T-cell activation was characterized by marked redistribution of DNA assembly to a central DNA pattern and increased nuclear size. Notably, heterogeneity in DNA patterns recovered in cells induced into quiescence in culture, suggesting an internal regulatory mechanism for chromatin reorganization. Taken together, our results uncover an important component of plasticity in nuclear organization, reflected in chromatin assembly, during T-cell development, differentiation and transmigration.

}, keywords = {Animals, Antigens, CD, Antigens, Differentiation, T-Lymphocyte, Bone Marrow Cells, Cell Lineage, Cell Movement, Cell Nucleus, Chromatin, DNA, Hematopoietic Stem Cells, Lectins, C-Type, Lymphocyte Activation, Mice, Microscopy, Confocal, Models, Biological, Models, Statistical, Sequence Analysis, DNA, Spleen, T-Lymphocytes}, issn = {1932-6203}, doi = {10.1371/journal.pone.0043718}, author = {Gupta, Soumya and Marcel, Nimi and Talwar, Shefali and Garg, Megha and R, Indulaxmi and Perumalsamy, Lakshmi R and Sarin, Apurva and Shivashankar, G V} }